On Tuesday 20 November 2007, Kris Kennaway wrote: > Kris Kennaway wrote: > > Kris Kennaway wrote: > >> In the meantime there is unfortunately not a lot that can be done, > >> AFAICT. There is one hack that I will send you later but it is not > >> likely to help much. I will also think about how to track down the > >> cause of the contention further (the profiling trace only shows that > >> it comes mostly from vget/vput but doesn't show where these are > >> called from). > > > > Actually this patch might help. It doesn't replace lockmgr but it > > does fix a silly thundering herd behaviour. It probably needs some > > adjustment to get it to apply cleanly (it is about 7 months old), and > > I apparently stopped using it because I ran into deadlocks. It might > > be stable enough to at least see how much it helps. > > > > Set the vfs.lookup_shared=1 sysctl to enable the other half of the > > patch. > > > > Kris > > Try this one instead, it applies to HEAD. You'll need to manually > enter the paths though because of how p4 mangles diffs.
I rolled a tiny, simple, possibly braindamaged benchmark (but then again php code tends to be braindamaged): test.php includes 1000 different, essential empty files and is strated over and over from a shell script which counts the runs completed within 60seconds. 1-8,128 scripts are started in parallel. On a 2x dual Opteron running amd64 I get: stock RELENG_7 w/o patch ULE: jobs sum runs gain 1 617 1 2 784 1.27 3 939 1.52 4 1015 1.65 5 658 1.07 6 642 1.04 7 666 1.08 8 696 1.13 128 726 1.18 RELENG_7 patched ULE vfs.lookup_shared=1: jobs sum runs gain 1 637 1 2 784 1.23 3 973 1.53 4 1104 1.73 5 708 1.11 6 733 1.15 7 776 1.22 8 840 1.32 128 936 1.47 So there is still a lot of room for improvement here. I'll rebuild with lock profiling tomorrow and see what I can gather. Anything you'd like to see in particular? -- /"\ Best regards, | [EMAIL PROTECTED] \ / Max Laier | ICQ #67774661 X http://pf4freebsd.love2party.net/ | [EMAIL PROTECTED] / \ ASCII Ribbon Campaign | Against HTML Mail and News
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